Characterization and first results of an ice nucleating particle measurement system based on counterflow virtual impactor technique
L. P. Schenk1, S. Mertes1, U. Kästner1, F. Frank2, B. Nillius2,*, U. Bundke2,**, D. Rose2, S. Schmidt3, J. Schneider3, A. Worringen4, K. Kandler4, N. Bukowiecki5, M. Ebert4, J. Curtius2, and F. Stratmann11Leibniz Institute for Tropospheric Research, Leipzig, Germany 2Institute for Atmospheric and Environmental Sciences, Goethe University of Frankfurt am Main, Frankfurt am Main, Germany 3Max Planck Institute for Chemistry, Particle Chemistry Department, Mainz, Germany 4Technical University of Darmstadt, Institute of Applied Geosciences, Darmstadt, Germany 5Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), Villigen, Switzerland *now at: Max Planck Institute for Chemistry, Particle Chemistry Department, Mainz, Germany **now at: Julich Research Center, Institute of Energy and Climate Research, Troposphere (IEK-8), Jülich, Germany
Received: 11 Sep 2014 – Accepted for review: 26 Sep 2014 – Discussion started: 21 Oct 2014
Abstract. A specific instrument combination was developed to achieve a better microphysical and chemical characterization of atmospheric aerosol particles that have the potential to act as ice nucleating particles (INP). For this purpose a pumped counterflow virtual impactor system called IN-PCVI was set up and characterized to separate ice particles that had been activated on INP in the Fast Ice Nucleus Chamber (FINCH) from interstitial, non-activated particles. This coupled setup consisting of FINCH (ice particle activation and counting), IN-PCVI (INP separation and preparation), and further aerosol instrumentation (INP characterization) had been developed for the application in field experiments. The separated INP were characterized on-line with regard to their total number concentration, number size distribution and chemical composition, especially with the Aircraft-based Laser Ablation Aerosol Mass Spectrometer ALABAMA. Moreover, impactor samples for electron microscopy were taken. Due to the coupling the IN-PCVI had to be operated with different flow settings than known from literature, which required a further characterization of its cut-off-behavior. Taking the changed cut-off-behavior into account, the INP number concentration measured by the IN-PCVI system was in good agreement with the one detected by the FINCH optics for water saturation ratios up to 1.01 (ice saturation ratios between 1.21–1.34 and temperatures between −18 and −26 °C). First field results of INP properties are presented which were gained during the INUIT-JFJ/CLACE 2013 campaign at the high altitude research station Jungfraujoch in the Bernese Alps, Switzerland (3580 m a.s.l.).
Schenk, L. P., Mertes, S., Kästner, U., Frank, F., Nillius, B., Bundke, U., Rose, D., Schmidt, S., Schneider, J., Worringen, A., Kandler, K., Bukowiecki, N., Ebert, M., Curtius, J., and Stratmann, F.: Characterization and first results of an ice nucleating particle measurement system based on counterflow virtual impactor technique, Atmos. Meas. Tech. Discuss., 7, 10585-10617, doi:10.5194/amtd-7-10585-2014, 2014.